Hans Severin Jørgensen

Jørgensen Number and Arithmeticity

The Jørgensen number of a rank-two non-elementary Kleinian group Γ is J(Γ) = inf{|trX − 4|+ |tr[X,Y ]− 2| : 〈X,Y 〉 = Γ}. Jørgensen’s Inequality guarantees J(Γ) ≥ 1, and Γ is a Jørgensen group if J(Γ) = 1. This paper shows that the only torsion-free Jørgensen group is the figure-eight knot group, identifies all non-cocompact arithmetic Jørgensen groups, and establishes a characterization of coco...

Marignac and Jørgensen: Two Forgotten Inorganic Explorers.

The lives and contributions of Jean-Charles Galissard de Marignac (1817-1894) and Christian Klixbüll Jørgensen (1931-2001) are reviewed briefly.

Hans Arnold Heilbronn 1908-1975 Hans

Hans Meinhardt

Hans Meinhardt is a theoretical developmental biologist working at the Max-Planck-Institute for Developmental Biology in Tübingen. He has pioneered the use of mathematical modelling of embryonic pattern formation. He received his PhD from the University of Cologne in Physics. For a postdoctoral fellowship, he went to the European High Energy Laboratory CERN at Geneva. By collaborating in an exp...

Chair : Hans